120 likes | 224 Views
H(e,e’p) Analysis. Chris Crawford Blast Analysis Meeting 2004/09/24. elastic cuts Helastic based on Dec out-bending Hcbc – wire chambers for April in-bending data Hpt – TOF elastic new timing offsets for Feb,April data. background comparison of yields TOF only, WC
E N D
H(e,e’p) Analysis Chris Crawford Blast Analysis Meeting 2004/09/24
elastic cuts Helastic based on Dec out-bending Hcbc – wire chambers for April in-bending data Hpt – TOF elastic new timing offsets for Feb,April data background comparison of yields TOF only, WC AL,R, m GE/GM , PbPt projected errors Outline
Hcbc – Wire Chambers • [p,q,f,z]e, [p,q,f,z]p)q,f,z (5 extras) • pe:qe pp:qpqe:qpfe:fp ze:zp pmiss • need better resolution (current re-crunch)
Timing Offsets • flasher unstable for April runs • retiming method • refit flasher peaks • aligned elastic timing peak in sets of 5k events • overall relative offsets from cosmics • use WC f to extract position offsets, slope
Hpt TOF elastic cuts • cut on 48 TOF paddle combinations/side • fit (ptr+ptl):(ttr-ttl) to 2-d gaussian • elliptical cuts with parameter ns
Background Comparison background (%) # events/C • Helastic • Hcbc • Hpt
Yields Comparison • TOF cuts only (lr ntuple) • MC includes WC acceptance (see forward paddles)
Super-ratio Method 2 equations in P, R for fixed bin j independent polarization in each bin! 2n parameters Pj, Rj Global Fit Method fit ALj, ARj to above formalism with P, Rj n+1 parameters n+2 (+spin angle?) same advantage as super-ratio method PbPt still cancels i = left,right j = Q2 bin (1..n) b = spin angle Fit Method
Combined Datasets with Projected Errors • based on additional 325kC of data • 32% increase in density • 3.2£ reduction in errors compared with 50kC in April